tustvold commented on code in PR #3762:
URL: https://github.com/apache/arrow-rs/pull/3762#discussion_r1126772103
##########
arrow-cast/src/parse.rs:
##########
@@ -445,6 +446,237 @@ impl Parser for Date64Type {
}
}
+pub fn parse_interval_year_month(
+ value: &str,
+) -> Result<<IntervalYearMonthType as ArrowPrimitiveType>::Native, ArrowError>
{
+ let (result_months, result_days, result_nanos) = parse_interval("years",
value)?;
+ if result_days != 0 || result_nanos != 0 {
+ return Err(ArrowError::CastError(format!(
+ "Cannot cast {value} to IntervalYearMonth because the value isn't
multiple of months"
+ )));
+ }
+ Ok(IntervalYearMonthType::make_value(0, result_months))
+}
+
+pub fn parse_interval_day_time(
+ value: &str,
+) -> Result<<IntervalDayTimeType as ArrowPrimitiveType>::Native, ArrowError> {
+ let (result_months, mut result_days, result_nanos) =
parse_interval("days", value)?;
+ if result_nanos % 1_000_000 != 0 {
+ return Err(ArrowError::CastError(format!(
+ "Cannot cast {value} to IntervalDayTime because the nanos part
isn't multiple of milliseconds"
+ )));
+ }
+ result_days += result_months * 30;
+ Ok(IntervalDayTimeType::make_value(
+ result_days,
+ (result_nanos / 1_000_000) as i32,
+ ))
+}
+
+pub fn parse_interval_month_day_nano(
+ value: &str,
+) -> Result<<IntervalMonthDayNanoType as ArrowPrimitiveType>::Native,
ArrowError> {
+ let (result_months, result_days, result_nanos) = parse_interval("months",
value)?;
+ Ok(IntervalMonthDayNanoType::make_value(
+ result_months,
+ result_days,
+ result_nanos,
+ ))
+}
+
+const SECONDS_PER_HOUR: f64 = 3_600_f64;
+const NANOS_PER_MILLIS: f64 = 1_000_000_f64;
+const NANOS_PER_SECOND: f64 = 1_000_f64 * NANOS_PER_MILLIS;
+const NANOS_PER_MINUTE: f64 = 60_f64 * NANOS_PER_SECOND;
+const NANOS_PER_HOUR: f64 = 60_f64 * NANOS_PER_MINUTE;
+const NANOS_PER_DAY: f64 = 24_f64 * NANOS_PER_HOUR;
+
+#[derive(Clone, Copy)]
+#[repr(u16)]
+enum IntervalType {
+ Century = 0b_00_0000_0001,
+ Decade = 0b_00_0000_0010,
+ Year = 0b_00_0000_0100,
+ Month = 0b_00_0000_1000,
+ Week = 0b_00_0001_0000,
+ Day = 0b_00_0010_0000,
+ Hour = 0b_00_0100_0000,
+ Minute = 0b_00_1000_0000,
+ Second = 0b_01_0000_0000,
+ Millisecond = 0b_10_0000_0000,
+}
+
+impl FromStr for IntervalType {
+ type Err = ArrowError;
+
+ fn from_str(s: &str) -> Result<Self, ArrowError> {
+ match s.to_lowercase().as_str() {
+ "century" | "centuries" => Ok(Self::Century),
+ "decade" | "decades" => Ok(Self::Decade),
+ "year" | "years" => Ok(Self::Year),
+ "month" | "months" => Ok(Self::Month),
+ "week" | "weeks" => Ok(Self::Week),
+ "day" | "days" => Ok(Self::Day),
+ "hour" | "hours" => Ok(Self::Hour),
+ "minute" | "minutes" => Ok(Self::Minute),
+ "second" | "seconds" => Ok(Self::Second),
+ "millisecond" | "milliseconds" => Ok(Self::Millisecond),
+ _ => Err(ArrowError::NotYetImplemented(format!(
+ "Unknown interval type: {s}"
+ ))),
+ }
+ }
+}
+
+pub type MonthDayNano = (i32, i32, i64);
+
+/// parse string value to a triple of aligned months, days, nanos.
+/// Fractional units must be spilled to smaller units.
+/// Fractional parts of units greater than months are rounded to be an integer
number of months,
+/// e.g. '1.5 years' becomes '12 mons + 6 mons', returns (18, 0, 0)
+/// Fractional parts of months, weeks, days, hours, minutes, seconds and
milliseconds are computed
+/// to be an integer number of days and nanoseconds, assuming 30 days per
month and 24 hours per day,
+/// e.g., '1.75 months' becomes '1 mon + 22 days + 12 hours', returns (1, 22,
12 * `NANOS_PER_HOUR`)
+/// leading field is the default unit. e.g. leading field is `second`, `1` =
`1 second`
+fn parse_interval(leading_field: &str, value: &str) -> Result<MonthDayNano,
ArrowError> {
+ let mut used_interval_types = 0;
+
+ let mut calculate_from_part = |interval_period_str: &str,
+ interval_type: &str|
+ -> Result<(i32, i32, i64), ArrowError> {
+ // @todo It's better to use Decimal in order to protect rounding errors
+ // Wait https://github.com/apache/arrow/pull/9232
Review Comment:
```suggestion
// TODO: Use fixed-point arithmetic to avoid truncation and rounding
errors (#3809)
```
--
This is an automated message from the Apache Git Service.
To respond to the message, please log on to GitHub and use the
URL above to go to the specific comment.
To unsubscribe, e-mail: [email protected]
For queries about this service, please contact Infrastructure at:
[email protected]
